MacBook Pro - MBP Headset Gaming woes

I'm about to give up on research/support for my PC350's (sennheiser). I wanted a quality gaming headset for online play so i purchased the pc350's. Issues:

1. Microphone jack will not work with line-level jack on MBP. Mic lvl jack requires different (amped) voltage.

2. Lack of soundstage/bass/oomph on pc350's. I read this is because of my onboard audio which i believe to be true. Although everything sounds flat/dull i can hear clarity in music i have never heard before (using standard headphones).

3. Positional audio and other game sound effects are non existent. I was naive to think these headphones would solve my problems. At first glance research shows onboard audio to be disgusting and the culprit but some threads suggest the MBP onboard audio is capable of dolby (etc) when an optical source is connected. Trying to salvage my headphone purchase and justify my laptop I went looking for a headphone jack to optical adapter. I keep reading i need 'mini-toslink' but im not sure i understand this correctly. I'm just trying to plug my headphones (3.5mm headphone male connector) into an adapter whose end would be an optical male end. So Female 3.5mm end (plug headphone in) with male optical out (or toslink so that i can plug it into my laptop and awaken its dolby capability).

Does that exist for #3? Because all of the adapters i see for 'mini-toslink' are optical-headphone (i dont want optical female) or optical-optical. Also I've considered sound cards to plug into the express port but the ones offered by creative all require windows for its driver package (i game mainly in osx). Only 2 minor options for creative remain which are XMOD and Xgo! but I'm unsure if those offer a powered mic input to get my mic working properly.

I've dabbled with websites like: Long & McQuade (living in calgary), but their 'soundcards' are mainly for recording musicians and i'm not even sure will offer me the decoding i need for games/powered mic input.

I've contemplated getting different USB headphones but I can't find any that match the quality of these pc350's! There is a new g35 headset from logitech but it requires windows and ive read a thread stating a mac user wasn't able to get its mic to function properly in OSX. I need some kind of solution to my poor sound quality and line-level/mic-level problem. I'm trying to hold onto these pc350's but im not sure its meant to be. I feel this problem affects all serious mac gamers and i'd like to discuss what they did to overcome this.

I think it's just a compatibility issue with the requirements of the pc350's. There might be a connection issue, or the headset might just need more power going into it. Have you tried going on music/audio forums? They might know more info about this kind of stuff. How about the apple store?
I gotta say though, I play CoD4 and talk through the built in mic and it works perfectly! I also use the standard iPhone headset and that also works great!

I think it's just a compatibility issue with the requirements of the pc350's. There might be a connection issue, or the headset might just need more power going into it. Have you tried going on music/audio forums? They might know more info about this kind of stuff. How about the apple store?
I gotta say though, I play CoD4 and talk through the built in mic and it works perfectly! I also use the standard iPhone headset and that also works great!

On a side note, the iPhone handsfree/earbud headset works amazing with Skype as well. Doing comp<>comp calls sound pretty good too.